a = input()
b = input()
c = a + b
if c == "x" * len(c):
    print(0)
else:
    ans, h = 0, 1

    for i in range(len(c)-1):
        if c[i] == "o" and c[i+1] == "x":
            h = 1
        elif c[i] == "o" and c[i+1] == "o":
            h += 1
        ans = max(ans, h)

    print(ans)